OpenACC Tutorial - Adding directives: Difference between revisions

The results are correct. However, not only do we not get any speed up, but we rather get a slow down by a factor of almost 4! Let's profile the code again using NVidia's visual profiler (<tt>nvvp</tt>).

[[File:Nvvp-pic0.png|thumbnail|300px|NVVP profiler|right]]

[[File:Nvvp-pic1.png|thumbnail|300px|Browse for the executable you want to profile|right]]

One graphical profiler available for OpenACC applications is the

[https://developer.nvidia.com/nvidia-visual-profiler NVIDIA Visual Profiler (NVVP)].

Consequently, if the executable is not using the GPU, you will get no result from this profiler.

When [[Visualization/en#Remote_windows_with_X11-forwarding|X11 is forwarded to an X-Server]], or when using a [[VNC|Linux desktop environment]] (also via [[JupyterHub#Desktop|JupyterHub]] with two (2) CPU cores, 5000M of memory and one (1) GPU),

it is possible to launch the NVVP from a terminal:

<translate>

# After the NVVP startup window, you get prompted for a ''Workspace'' directory, which will be used for temporary files. Replace <code>home</code> with <code>scratch</code> in the suggested path. Then click ''OK''.

# Select ''File > New Session'', or click on the corresponding button in the toolbar.

# Click ''Finish'' to start profiling the executable.

This can be done with the following steps:  

# Start <tt>nvvp</tt> with the command <tt>nvvp &</tt>  (the <tt>&</tt> sign is to start it in the background)